The regulations prohibit drivers from operating a vehicle when they're fatigued, driving more than 14 consecutive hours without taking 10 hours off and making false reports about their duties.

Trooper James Sauter was pulled over on the left shoulder on I-294 south of Willow Road when he was hit from behind by Bokelman's truck. Both vehicles burst into flames, and 28-year-old Sauter was killed.

An autopsy revealed Sauter died of "thermal injuries from a post-crash fire," the Cook County Medical Examiner’s office said. He also suffered inhalation and minor closed head injuries, according to the medical examiner’s office.

"More than an outstanding trooper, he was an outstanding human being," said fellow trooper Jason Bradley. "Great hearted, a family man. He loved his wife and loved his family, and he was always willing to help others not only as a trooper but outside of work as well."

Director: Trooper Was 'Talented, Wonderful Police Officer'

Trooper James Sauter represented everything good about the police department," Illinois State Police Director Hiram Grau said Friday. "Our focus now is to be with the Sauter family every step of the way and to support his fellow officers and colleagues."

(Published Friday, March 29, 2013)

Bokelman turned himself in to Illinois State Police Wednesday. A judge set bond at $125,000.